Potential signs of trouble are popping up again in the form of tighter conditions in short-term funding markets, which act as the indoor plumbing of the financial system, and this may require the Federal Reserve to take action relatively soon.Two measures of funding-market liquidity, known as the Secured Overnight Financing Rate and the Tri-Party General Collateral Rate, have both crept back above 4% during the past week, but remain off their late-October peaks. Both rates are derived from the U.S. overnight repo market, which acts a critical source of short-term funding for a wide range of financial institutions. ... (full story)